1. Field of the Invention
The present invention relates to an elongated-strip-article processor mounted to an ink jet printer or the like for moving the elongated strip article, such as a fastener or the like, to be printed.
2. Description of the Related Art
Japanese Patent Laid-open Publication No. 3-69658 and Japanese Patent Laid-open Publication No. 5-330085 respectively discloses an ink jet printer for applying printing to the elongated strip article such as a fastener or a surface fastener. The ink jet printer comprises a processor for conveying the elongated strip article to be printed. This type of elongated-strip-article processor has conveying passages for a plurality of elongated strip articles, the passages being arranged in a substantially horizontal posture below print heads having ink jet nozzles. A driving roller abuts on one faces of the elongated strip articles and follower rollers abut on the driving roller via the elongated strip articles, thereby advancing the elongated strip articles at a predetermined speed intermittently by predetermined lengths for printing. The driving roller is mounted on only one side of the print head relative to a conveying direction of the elongated strip articles as disclosed in Japanese Patent Application Laid-open No. 3-69658, or mounted on both sides of the print head as disclosed in Japanese Patent Application Laid-open No. 5-330085.
In the above prior art, the ink jet printer can clearly print fine patterns, but there has been a problem that the printed patterns are disarranged on a product if the elongated strip article is slackened or stretched. Particularly when a plurality of elongated strip articles are mounted to the ink jet printer, because the respective elongated strip articles are slackened or excessively stretched in different states, each of the elongated strip articles needs to be brought into an optimum state by individual adjustment when conveyed. However, it has been difficult to easily adjust a tension per each elongated strip article.
The present invention has been accomplished with above prior art in view. So, it is an object of the invention to provide an elongated-strip-article processor which can accurately convey a plurality of elongated strip articles on an ink jet printer respectively with optimum tensions.
To achieve the above object, according to the invention, there is provided an elongated-strip-article processor including a processing section for applying printing to a plurality of continuous elongated strip articles along conveying passages of the elongated strip articles by an ink jet printer and a conveying section which is disposed in a vicinity of the processing section for intermittently conveying the elongated strip articles by a predetermined length. The processing section may include a print head and a drier unit of the ink jet printer, and the conveying section may be a print roller for conveying the elongated strip articles.
The elongated-strip-article processor further includes tension adjusting sections, such as dancer rollers, disposed upstream and downstream out of a range of the conveying passages including the processing section and the conveying section for adjusting tension of each of the elongated strip articles at a constant value, and sensors respectively provided at the tension adjusting sections as the dancer rollers. Each of the dancer rollers moves up or down according to a length of slack of the elongated strip article in contact with the dancer roller. The sensors detect the length of slack of each elongated strip article by detecting positions of the dancer rollers. Further, the processor includes feed sections disposed respectively upstream of the upstream-side tension adjusting section and downstream of the downstream-side tension adjusting section so as to correspond to the individual elongated strip articles. Each of the feed sections switches between a state of positively feeding each elongated strip article and a state of suppressing feed of each elongated strip article based on detection signals from the respective sensors.
Each of the feed sections further includes a driving roller disposed under the elongated strip articles and having a rotation axis perpendicular to a feed direction of the elongated strip articles, at least one retainer disposed under the elongated strip articles and in parallel to the driving roller for retaining the elongated strip articles, a plurality of follower rollers disposed above the elongated strip articles and in parallel to the driving roller, and a plurality of retaining members above the elongated strip articles so as to face the retainer via the elongated strip articles, the follower rollers or the retaining members being adapted to be alternatively pressed against the driving roller or the retainer so as to clamp the elongated strip articles between the follower rollers and the driving roller or between the retaining members and the retainer. For example, each pair of the follower roller and the retaining member are respectively and rotatably attached to opposite ends of a single actuator having a rotation shaft substantially at a center of the actuator. The actuator has at one end portion thereof a moving means, such as an air cylinder, for pivotally moving or swinging the actuator about the rotation shaft and for pressing the follower roller or the retaining member against the driving roller or the retainer via each of the elongated strip article.
The retainer of the feed section may be a driving roller disposed in parallel to the first-mentioned driving roller and rotating at a lower speed than the first-mentioned driving roller. In this case, the follower roller is also pressed against the second-mentioned driving roller.
Each of the driving rollers may be a single roller with respect to a plurality of elongated strip articles. The numbers of the follower rollers and the moving means thereof disposed above the driving rollers may correspond to the number of the plurality of elongated strip articles conveyed in parallel to each other.
In the elongated-strip-article processor of the invention, the elongated strip articles are conveyed by predetermined intermittent conveyance. If a feed amount of each elongated strip article becomes larger than that intermittent conveying amount so that a length of each elongated strip article becomes excessive, the corresponding dancer roller moves down. Then, the corresponding sensors detect that the dancer roller has reached its lower limit position, and a signal is transmitted to the corresponding moving means such as a cylinder. Then, the cylinder moves the corresponding retaining member or the corresponding follower roller to move down to be pressed against the corresponding retainer, or to be pressed against one of the corresponding driving rollers rotating at a lower rotation speed through the elongated strip article. Thus, the elongated strip article is retained by the retaining member or conveyed slowly by the slow driving roller and the follower roller. As a result, the feed amount of the elongated strip article decreases, so that the dancer roller does not further move down. As a result, the length of the elongated strip article gradually decreases, and the corresponding dancer roller moves up.
If the corresponding dancer roller moves up to reach its upper limit position, the corresponding sensors detect that the dancer roller has moved up and a signal is transmitted to the moving means such as a cylinder. Then, the cylinder moves, such that the corresponding follower roller moves down to be pressed against the other one of the corresponding driving rollers rotating at a higher rotation speed through the elongated strip article. Thus, the elongated strip article is conveyed by that driving roller and the follower roller. As a result, the feed amount of each elongated strip article from a feed bobbin increases, and the dancer roller does not move up, so that the length of each elongated strip article gradually increases, and the corresponding dancer roller moves down. Thus, tension of the elongated strip article can be maintained at a constant value at the processing section.
As mentioned above, the dancer rollers move between the lower limit position and the upper limit position which is sufficient to give each elongated strip article a length of slack, for preventing the elongated strip article from begin excessively tight or loose between the intermittent conveying section and the feed section. Further, the tensions of the elongated strip articles are adjusted by predetermined weights of the dancer rollers so that abnormal fluctuations of the tensions can not occur.